Drop the box from the car, disassemble into all it little pieces. Replace the seals and reassemble correctly, in the process bring everything back to spec. Then reinstall the box.
I opted to farm this one out. Glad I did too, because one of the prior owners had tried to compensate for missing steering coupler bushing by overtightening the coupler. In the process the hex of the cap screw was stripped. That made removing the box a real be-itch for the Tech.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.